How to divide moss phlox
Has your moss phlox spread too far? It’s easy to divide. Spread the foliage apart and cut through the roots along the dividing line, which you can see in the top photo at left, making sure all the roots on the division are severed from the main plant. Then use a trowel to loosen the roots and release the division from the ground so you can lift it. We’re taking it out of a gravel path in the lower photo. You may need to loosen the soil around the plant if it’s in your garden. A large division like this one can be cut into smaller sections before replanting.
Use a trowel or cultivator to loosen up the top few inches of soil where you intend to replant moss phlox, just lay the phlox on top of the prepped area and press it onto the soil. Using soil or compost, make sure exposed roots are covered, but try not to bury the stems.
Creeping phlox (Phlox subulata) isn’t the only plant you divide using this technique. These plants also have shallow roots:
Creeping thyme Thymus serpyllum
Sedum Sedum spp. and hybrids